Mid Sweden University

Using energy systems analysis, we examine the potential to reduce CO 2 emissions and oil use by integrating motor biofuel production with pulp mills. BLG-DME (black liquor gasification with di-methyl ether production) is compared with solid biomass gasification with BIG-FT (solid biomass gasification with Fischer-Tropsch fuel production). The studied systems are expanded with stand-alone production of biomass-based electricity and motor fuel so that they yield the same functional unit in terms of motor fuel and electricity as well as pulp or paper product, in order to facilitate comparison. More motor biofuel can be produced in integration with the studied mills with BLG-DME than with BIG-FT because the black liquor flow is large compared with other fuel streams in the mill and the integration potential for BIG-FT is limited by the mill’s heat demand. When both systems are required to produce the same functional unit, the BLG-DME system achieves higher system efficiency and larger reductions in CO 2 emissions and oil use per unit of biomass consumed. In general, integration of motor biofuel production with a pulp mill is more efficient than stand-alone motor biofuel production. Larger reductions in CO 2 emissions or oil use can, however, be achieved if biomass replaces coal or oil in stationary applications. © 2012 Elsevier Ltd.

Swedish energy strategies for transportation, space heating and pulp industries were evaluated with a focus on bioenergy use. The aims were to 1) study trade-offs between reductions in CO 2 emission and oil use and between Swedish reductions and EU reductions, 2) compare the potential contributions of individual reduction measures, 3) quantify the total CO 2 emission and oil use reduction potentials. Swedish energy efficiency measures reduced EU CO 2 emission by 45-59 Mt CO 2/a, at current biomass use and constant oil use. Doubling Swedish bioenergy use yielded an additional 40 Mt CO 2/a reduction. Oil use could be reduced, but 36-81 kt of reductions in CO 2 emission would be lost per PJ of oil use reduction. Swedish fossil fuel use within the studied sectors could be nearly eliminated. The expansion of district heating and cogeneration of heat with a high electricity yield were important measures. Plug-in hybrid electric cars reduced CO 2 emission compared with conventional cars, and the difference was larger with increasing oil scarcity. The introduction of black liquor gasification in pulp mills also gave large CO 2 emission reduction. Motor fuel from biomass was found to be a feasible option when coal is the marginal fuel for fossil motor fuel production. © 2012 Elsevier Ltd.

We compare different options for the use of lignocellulosic biomass to reduce CO2 emission and oil use, focusing on polygeneration of biomass-based motor fuels and electricity, and discuss methodological issues related to such comparisons. The use of biomass can significantly reduce CO2 emission and oil use, but there is a trade-off between the reductions in CO2 emission and oil use. Bioelectricity from stand-alone plants replacing coal-based electricity reduced CO2 emission by 99 kg per GJ biomass input but gave no oil use reduction. Stand-alone produced methanol replacing diesel reduced the CO2 emission with 38 kg and the oil use with 0.67 GJ per GJ biomass, indicating that a potential CO2 emission reduction of 90 kg is lost per GJ oil reduced. CO2 emission and oil use reduction for alternatives co-producing fuel and electricity fall between the stand-alone alternatives. Plug-in hybrid-electric vehicles using bioelectricity reduced CO2 emission by 75–88 kg and oil use by 0.99–1.2 GJ, per GJ biomass input. Biomass can also reduce CO2 emission and/or oil use more efficiently if fossil-fuel-fired boilers or electric heating is replaced by district heating from biomass-based combined heat and power generation. This is also true if electricity or motor fuel is produced from black liquor gasification in pulp mills or if wood is used instead of concrete in building construction. Biomass gasification is an important technology to achieve large reductions, irrespective of whether CO2 emission or oil use reduction is prioritised.

We study biomass-based motor fuel production integrated with pulp and paper mills and calculate oil use and CO2 emission balances. We compare two different processes – (1) integration of solid biomass gasification and FT diesel synthesis with a mill and (2) black liquor gasification (BLG) and methanol synthesis. CO2 emission and oil use balances are calculated and compared to alternative uses of biomass. We conclude that motor fuel production integrated with pulp mills is a more efficient option than stand-alone production of motor fuels. However, CO2 emissions can be more efficiently reduced if biomass replaces coal. BLG and solid biomass gasification have high system efficiencies. In a modern mill with low steam demand, the integration potential for solid biomass gasification is limited. If the studied systems are expanded with stand-alone production of fuel, so that the systems produce the same amount of motor fuel per t pulp, the BLG system has higher system efficiency due to the larger integration potential per t pulp.